Radiation contamination maps of perception, created by people at the blog called "Bearded Pirates (あごひげ海賊団）" and posted on 9/8/2011, look pretty accurate for mapping the perception of contamination.

Contamination as perceived by people in Tohoku: Fukushima and part of neighboring prefectures. This is very close to what is being reported in the mainstream media, by the way.

Contamination as perceived by people in Kanto: almost entire Tohoku and northern Kanto.

Contamination as perceived by people in Hokkaido: almost entire Tohoku, Kanto, and Chubu. It stops right about Lake Biwa.

Contamination as perceived by people in Kansai: entire Kanto and Tohoku, half of Chubu, and 2/3 of Hokkaido.Contamination as perceived by people in Okinawa: almost entire Japan except for Kyushu and part of Shikoku and Chugoku.

Contamination as perceived by people outside Japan: entire Japan

Contamination as perceived by Japanese politicians: area around Fukushima I Nuclear Power Plant.